For the initial planning of a mission, you don´t need to be connected to the drone. You will just need the controller.

1. Fig. 1: Choose "Flight route"
2. Fig. 2: Flight route menu
   1. Here you will see all the routes you created before
   2. You can add new missions by clicking the plus in the top right corner
3. Fig. 3: Choose "Create a route"
4. Fig. 4: Zoom in to the area you roughly want to map
5. Fig. 5: Tap the outline corners of the area that you want to map
   1. You can add new corners in between by clicking the small +-Icons on the individual lines
   2. Click the checkmark in the top left corner to save your mapped area

1. Fig. 6: Select "M3E Series" if flying the DJI Mavic 3M
2. Fig. 7: Select "M3M" if flying the DJI Mavic 3M
3. Fig. 8: Select if you want to also take MS images
4. Fig. 9: First part of the settings
   1. Give the mission a good name
   2. Ortho Collection for normal cartography
   3. Oblique Collection for 3D reconstruction
   4. Ortho GSD is used to set roughly the resolution in cm/px of the map you want to get in the end. This will automatically adjust the needed height, so you won't need to change that
   5. ASL/ALT is the reference that is used to determine the flight height. You can normally leave it at ALT, but you need to make sure that there is no object at the flight height of the drone in the end. For example, you fly at the foot of a 100m tall hill and you set the flight height to 50m relative to your starting position… well that wouldn´t be that helpful.
5. Fig. 10: Second part of the settings

For reference here also an official video by DJI: How To Start A Mapping Mission And Create 2D Maps- Episode 9